1. Field of the Invention
This invention relates to a reflector for a light-emitting semiconductor device that exhibits high light reflectance and is resistant to light transmission, a resin composition that is ideal for forming this reflector, and a composite particle that is added to the resin composition.
2. Description of the Related Art
Conventionally, reflectors for light-emitting semiconductor devices have typically been formed from compositions prepared by adding a white filler material such as titanium oxide, magnesium oxide or zinc oxide, and silica and the like to an epoxy resin or a silicone resin.
However, reflectors formed from a thermoplastic resin or an epoxy resin or the like have a problem in that, when a high-brightness LED or the like is installed, the resin degrades and yellows due to the effects of temperature and light (Patent Documents 1 and 2). Further, another problem arises because a large amount of a fine powder of titanium oxide or the like must be used to ensure a white color, and as a result, the flowability of the resin deteriorates, and when the reflector is molded by transfer or injection molding or the like, molding defects such as incomplete filling and voids tend to occur more frequently (Patent Document 3).
On the other hand, if a silicone resin is used, absolutely no discoloration of the reflector occurs even when a high-brightness LED is installed. However, if silica is used as a filler material, then a problem arises in that some of the emitted light escapes due to similar refractive index of silica to that of the silicone resin (Patent Document 4).